Method of electrochemical treatment of unsaturated hydrocarbon compounds resulting from the cracking of oils



1,585,573 D. L. THOMAS TURATED HYDROCARBON RESULTING FROM THE CRACKINGOF OILS Ma 18 192s.

METHOD OF ELECTROCHEMICAL TREATMENT OF UNSA COMPOUNDS Original FiledApril QuinIIiMqIuIqIuInlullillglqlnlnlnlulnlnlgllnlnlul INVENTO $610124A7 7/01 ATTORNEY l Pate ted 18,1926.

PATENT orsica;

mm L. :rnomns, or NE YORK, N. Y.

POUNDs RESULTING IROM THE ,CRAQKIN' G'OF- OILS.

Original application filed April 24, 1919, Serial No. 2a2,425. Dividedand this 9, 1925. serial-r0. 7,886.

I This invention relates to the electro- .a detriment, whils t duringrecombination,

chemical treatment of unsaturated hydro-r asit favors reunion of thecracked products,

carbon compounds resulting from the heat cracking ofoils and has for itsobjects the ,6 stabilization --of such compounds through thehydrogenation, polymerization or recombination thereof whereby the yieldof condensable liquids is incrasedand valuable light hydrocarbon liquidsof superior 1 quality to that ordinarily produced by the usual highpressure cracking process can be obtained by' the simple distillation ofthe resultant products without necessitating expensive acid refiningtreatment. a In my co-pending application No. 292,425 for process andapparatus for converting high-boiling oils orhydrocarbons into stablelow boiling oils or hydrocarbons filed'April 24, 1919, of which thisapplicationis a true division, there is described a novel method andapparatus for the pyrogenetically cracking of hydrocarbons by heat andpressure for the purpose of producing unsaturated hydrocarbon compoundswhich are suitable for being subjected to the electro chemical treatmenthereinafter described.

As stated in said pending application, the amount of heat required isthat which is necessary to furnish the expansive force 3 needed to bringabout rupture of 'the original hydrocarbon molecule, whilst pressure isnecessary to force together the resulting nascent reactive products intomore concentrated and intimate relationship so that reactions involvingnew molecular arrangements can thereafter take place in a. second andpreferably separate stage of the proc- I ess. The reactions of this last'stage of the process are greatly facilitated by the action 40 of theelectric current, which plays the part 1 of a catalytic element,.aflecting the timefactor of the reaction andmaking possible theaccomplishing of results that are unattainable-by other and lessenergetic means. As all cracking operationsvrequire more or lessmechanical force for their development, it iscustomary to obtain thisforce from the expansive power of the 'oil-vapors developed underpressure. Thepressure in this last mentioned case,-when present. duringthe decomposing stage ofrthe process, naturally opposes the expansiveforce need ed-to bring about rupture of the hydrocaritlis a sinequa-non'of operation.v

applieationfiled February From these facts I have ascertained that thecracking operation should take place-in the following series of steps:

cient working force to operate the ap-.

paratus.

2nd. Cracking ofthe oilvapor at higher temperatures, for example at from500 to 800 0., under low pressure to produce.

chemical dissociation. 3rd. A condensation of the cracked products,under high pressure in order molecular recombination.

under pressure, to the silent electric dis charge or electric corona,either Before or after condensation to the liquid state, to producehydrogenation and polymerization.

4th. Treating-the cracked products While At present there are at leastthree-recognized standard methods of cracking oils by means of heat andpressure, each capable of illustration by a type.- First, the so-calledBurton-process, consisting of heating a large body of liquid oil in alarge tank or still, and condensing the vapors generated- Second, .thesocalled Rittman-process, consisting. of heatj mg oil-vapors underpressure, in a large therein under pressure.

(12 inch) tube and then condensing the cracked products soproduced'nnder pressure.

Third, the sol-called Hall-process, which consists of heating the oil ina long coil of small bore pipe, (1 inch diameter and 600 feet long)releasing the pressure so produced, by expanding thevapor down toatmospheric pressure in a large tankor. chamber and then" againrecompressing the gases andvapors by means'of a mechanical compressor,in order to polymerize them, and

then final-ly'condensing the resulting prodnets to liquid underpressure.

,To'. these may be-added a fourth type, as exemplified in mysai'dcgpending application, wherein an oil, as fuglgoil of, 850 S. G. isvaporized under pressure and the vapor soIgenerated, passed into aregion of low pressure. High temperature is then applied bon .molecules,hence, at this point it is to the vapors in this region of low pressureto favor pressure for recombination and polymerization.

. Finally they are subjected to the action ofthe silent electricdischarge, in this region of high pressure, either whilst" in the vaporstate or after condensation to the liquid state,and finally. condensingand removing the finished product. All this to be ac-' comp'lishedwithout the use of mechanical Oneof the features of this invention is abeing in a liquid state.

Fig. 2 is also an elevation partially in sec-.

pumps or compressors.

The specific exa'mpleof a one tube mstaL .lation is fully set forth-anddescribed in .the following specification and drawings forming a' partthereof in' which Figure 1 is an elevation, partially 1n section of aform ofthe apparatus wherein the cracked products are first treated in adigester, and are then submitted to the action of a corona or silentelectric discharge, either direct or alternating, the treated p'roductstion of a form wherein the di'gester is dispensed with its place beintaken by an electrical treating chamber a apted to function as adigesterand polymerizer, by acting on all of the cracked products whilstexistent .geo.

in the form of vaporsand gases before being1 condensed to the liquidstate. Figs. 3' an 4 show longitudinal and cross sections of the piecesof iron pipe used in the digester.

meansby' which the unsaturated hydrocarbons inevitably found in allproducts that.

- are cracked by heat maybe permanently deposits a gummy resinousresidue very instabilized. Thesecompounds have a very deleterious effecton motor-fuel produced by cracking as such fuels in the course of timejuriousto the action of the valves of internal combustion engines. The.removal of such products by meansof sulphuric acid is 'a' very seriousproblem of the refinery, and

I one that so far has defied a satisfactory solution on account of thelarge loss of valuable material involved. These products if *they could'be stabilizedwould form a very valuable-addition tothe fuel itself,adding greatly to its thermal or heating capacity. It is purposed toshow herein how this result 7 can be accomplished. As a preliminary to 4both alternating and direct, on various sat-. "'urated and unsaturatedhydrocarbon compounds leads to the conclusion, that as a a presentation.of the means to be used fdr this purpose, it may be stated that vtheeffects are predicated on the experimental results attained by such menas J. N. Collie, H. Jackson and- D. Northall Lowrie, and F. Skaupyworking with the electric current in the form of a corona or silentelectric dis- ,charge through hydrocarbons, wherein it is shown that theaction of electric discharges,

general rule, saturated compounds aref broken down to simpler molecules,whilst un-. saturated-compounds (such as ethylene and" olefines) I areconverted into complex polymerized substances,'thus, in the case ofparallin derivatives the general tendency is for unsaturated bodies togive polymerized varij etres under the influence of thesilent'discharge, whilst saturated compounds, under similar conditions,yield substances of sim- 7 pler structure. At the same time it must be.

. pointed out that the silent electric discharge under proper conditions(such as whenhydrogen or gases containing hydrogen are prescnt) has thepower to bring about hydro- 0 genation of unsaturated compounds, thishas been pointed out by A. de Hemptinne in his U. S. Patent No. 797112.Considerable use -is made of this last feature because in the methodoutlined herein, it is proposed to pass the gases generated in crackingthe'hy drocarbons, into the electric field along with the condensablehydrocarbons or the liquids derived therefrom, the wholevbeing treatedin such manner that the gases, and the con--a0 densable vapor ,or theliquid are brought into intimate contact with each other whilst beingsubmitted to the action of the electric efliuvia. The result oftheaction will be to, bring abouta union of more or less of these gaseswith. the vapor'or liquid, along with polymerization of unsaturatedcompounds, whether existant in gas, vapor or liquid, thus materiallyincreasing the yield of condensable liquids. Moreover it will'be foundthat 101 the resultant liquids are, perfectly stable,. the ,double-bondsof the unsaturated moleculeshaving been satisfied or eliminated bycombination, thus-,'stabi lizing the product.

-\V hen purified by a further simple distilla- 10% tion the liquids areready for use.

.One method of carryingout the process is illustrated in Figure 1. Herean electrical coronaor silent electrical discharge is created directlyin 'the body of the liquid hy- 11" drocarbom To many, the idea ofproducing a corona discharge directly in a body of liquid oil, will seemrevolutionary, the phenomena however, is well known to elec-- tricalengineers; see articlesby F. W. Peck, 11 Jr., in The General ElectricReview, vol. 18 -1915 page 821 and-by W. S. Moody and p G. Faccioli inTrans. Amer. Inst. Electrical Engineers vol. 281909' page 769'.

In its way electrical corona mod is quite 12 as distinct a phenomenaas'in.v gases. or. air,

The d ielectric strength of oil, that is to it tional to pressure.

say, the disruptive gradient or voltage required to bring the ions uptoan ionizing Collision velocity, seems to'be fairly low,- and accordingto F. W. Peck, Jr., is about 36 kilovolts, therefore it may be said oilhasa Y low dielectric strength in bulk. n

Referring to Figure 1, the pipe a is adapted to receive cracked productswhile still under the final pressure and at the temperatures to whichthey were subjected in the final space or chamber of the cracking unitof the refinery and without previous cooling of the said-products, suchfor example as the lower diverging Venturi mouth piece of the apparatus(not shown) described in my co-pending application aforesaid.

It is to be understood that the object of the digest'er .7) is to treatthe hydrocarbon material by exposing it, to large surfaces 1)" by whichit is naturally adsorbed, whilst the speed of travel of the vapors isreduced to a minimum. Such surfaces exert a catalytic or some similareffect on the cracked material which is in a highly reactive condition,bringing about hydrogenation, polymerization and recombination of thenascent fragments of the original hydrocarbon molecules into newmolecular arrangements. This action is of course assisted by pressure,because, according to the law of mass action, reaction velocity isproportional to concentration and concentration is directly propor-Surface action has a great deal to do with the effects produced as nalof Physical Chemistry, June 1918, page is in liquid or gaseous statewhen brought is pointed out by Professor Wilder Bancroft in a Note oncontactcatalysis J our- 433, wherein it is shown that the equilibriumand velocity relations of physical substances is markedly altered byadsorption, much freer play being given to physical and chemical forcesthereby. Whatever the cause may be, the action is unquestionable,

being more cumulative than instantaneous and it takes placewhether' thehydrocarbon into contact with the material.

It appears that two entirely'difierent reactions are involved in the;formation 'of light hydrocarbons. Thefirstone involves slitting ofsaturated bodies into saturated and unsaturated, parafins; and olefinesof lower molecular weight resulting, with the splitting out of hydrogen,and consequent increase in volume of cracked produbts. Diminishedpressure facilitates and accelerates this stage. The next step, however,requires the condensation and hydrogenation of the unsaturated bodies,and pressure naturally favors this. It is true that hydrogen may splitout also at this point, but even so, condensation and hydrogenation isdifficult to effect under diminished pressure, therefore sufiicientpressure must be provided to effect this condensation since the naturaltendency of pressure is to force homogeneous Figure 1, shows how thismay be carried out.

Here, in this method the condensed liquids along with thenon-condensable gases, are led into a receiving tank space, 64, formedusually in the upper part of the treating receptacle, 65, by means of apipe 66, and valve, 67, that connects with the condenser 68. Thereceptacle 65, preferably consists of strong steel tube having an innerenameled surface 65' of glass, porcelain or other dielectric material,the dielectric surface serving to prevent danger of a short circuit whenthe oils are very bad and contain electrically conductive material, *atthe same time the dielectric is-useful insuring a uniformly distributedelectrostatic field. The upper portion of the receptacle, 65,is closedby an insulating stopper 7 0, thus separating and hermetically sealingoff the tank-space 64 from the main body of the receptacle 65. The mainbody of the receptacle is provided with an outlet tube 71 near its upperend, for the escape of the treated gases and liquids to, thestorage tankand recirculating gas-line 91. A11 electrically insulated metallic tubeor pipe 72 extending from the interior of the tank space 64 into thebottom of the main receptacle 65, serves to deliver the liquids'andgases discharged into the space 64 from the condenser to the bottomwardly outside of the tube 7 2 to the pipe 71.

-' This insulated metallic tube 72 constitutes the inner co-operatingelectrode to theouter walls .of the treating chamber 65 which form theouter electrode. As indicated,

this inner electrode is preferably provided with sharp projections,formed by thin metallic discs J spaced short distances apart by washerse of smaller diameter, thewholebeing held togetheron the pipe 7 2 bysuit-. v

The con struction is such that this inner electrode is ablescrew-connections and nuts.

separated a greater distance from the outer' electrode, at its ends,than at the region where the projections are provided and where theelectric action takes place. The oils and the gases in thoroughadmixture therewith, on being discharged into the lower part of thetreating chamber, rise to the v 4 discharge tube 71 and in so doing pass90 by a dynamic are following a spark-over, as v venting danger tooperators from electric shock. The positioning of the electrodes, .onewithin the other, is an advantageous one, as it gives a very denseelectrostatic field of high gradient near the inner electrode,. but ofrelatively low gradient at the outer electrode or wallof the treatingchamber which facilitates the production of the corona discharge. 4

" J The liquids after passage through the treating chamber are submittedto further simple distillation treatment, to remove polymerized resinousproducts and are then ready for use. The advantages of this a method oftreatment over that requiring the use of sulphuric acid, with its largeattendant loss of valuable material at once recommends the method to theattention of those interested in securing a rapid and economi- .cal'method of treating crackcd'hydrocaricons to render them suitable for themarket. Although I have disclosed a suitable form of apparatus forpracticing the invention, I do not limit myself to these special devicesor constructions herein specified, as I believe it is broadly new withme, to utilize the effects of, passing a high potential electric currentthrough a body of liquid hydrocarbons in order to effect thehydrogenation, polymerizationand synthesizing of the unsaturatedcompounds existing in such cracked oils as specified above as productssuitable for treatment.

- In the form of the invention disclosed in Fig. 2 the importantfunction of the digester of Figurel is dispensed'with, its place beingsupplied by' an electric polymerizer, adapted'to function both asdigester and olymerizer'by acting on all of the cracked hydrocarbonswhile they are in the .vapor state. This arrangement has certainadvantages due to the fact that not alone is the plant rendered morecompact, but the corona discharge'itself issomewhat easier to produceand maintain in vapors and in gas es than it is in liquids.

In order to make the construction plain, it

may be said that the cracked products are conducted by the pipe 0 to anelectrical treating chambers as shown, consisting of a steel tube about12 inches "internal diameter 7 and 15 ft. high. To its base is fitted aconical extension or sludge-box 78, having an'automatic-float-controlledsvalve 78, for removing liquid residues, aspreviously exa plained, and-which maintains the liquid level at thepoint 7 8"7 8",.

Suspended in the tube 0 and electrically insulated therefrom, isa hightension discharge electrode 79, formed of a inch steel rod, havingthereon in equally spaced relationship, thin metal discs about 3 inchesin diameter and spaced apart by metal washers 1 inch in diameter andinch thick. To the top of the electrode 7 9 one wire 80, of a hightension alternating current electrical transformer 81, is attached, theother wire 82 of the transformer being grounded at To the base oftheelectric-a1 treating chamber and in electrical contact therewitlr at thepoint 84, there is attached a Wire 85, which in itsturn is grounded at86. The objcct being to avoid danger of electrical shock whenthe-high-tension transformer is being operated. i

By causing acorona discharge to take place between the walls ofthe tubeand the central electrode,"oil-vapors on being passed -thro1ighthis tubeare subjectedto a series of intense electrical fields of high gradientnear the central electrode, provided the edges of' the discs, and theunsaturated products contained therein are rapidly polymerized and builtup according toprinciples already enunciated. The tube 0, should have aheat insulating jacket 1), around it to prevent loss of heat andconsequent undesired c011- densati'on at this point.

the vapors pass to the water-cooled condenser (58, by means of a pipe87, and here the cendensable portion of the cracked products is reducedto liquid formand flows into the storage tank90 the.non-condensab-legases escaping by way of the connection '88, to the pipe line 91' to bereturned to the system for recirculation therethrough forcarnying outthe various functions already specified.

The part played by electricity in this proce-jas should be clearlyunderstood, as it is important to grasp the idea that the current is notused for the purpose of decomposing the hydrocarbons, such decompositionas occurs being merely incidental, the main purpose and object in Viewbeing the hydrogenation and. polymerization of the cracked-products,

so as to completely stabil'ize'the resulting product. of the reaction.This the current as has been pointed out above.

does in a very thorough and rapid manner I am perfectly familiar withthe fact" that it has been proposed to use the electric current asa'meansof'decomposing hydro- Y carbons in order to producelower-boiling.

products, theuse of direct-current for this purpose having been patentedby J H. Robertson (U.- S. 'Pat.'No. 1238339) and the use 'of'alternating-current having been patented by. L. B. Cherry (U. S. Pat.No.

1229886) But so far as my knowledge goes, it has never been proposed touse the elec tric current as a means to bring about hydrogenation andpolymerization of the cracked products, after the cracking operationitself has been completed by heat and pressure in the usual manner. Thisforms a clear and distinct line of demarkation between this method andthe processes referred to above. In the one case it acts as the crackingmedium, in the, other case it acts as the synthesizing medium. This useof the current com pletely eliminates the gummy material deposited bymost cracked gasolenes' and which is due to a slow polymerization of theunsaturated compounds which they contain. These compounds are completelypolymerized once and for'all by the current and are then, aftercondensation, removed by a simple distillation of the final product. Amaterial saving inthe way of refinery treatment is thus efi'ected and amuch higher grade product produced.

Under the influence of the pressure and the action of the electriccurrent, recombination, polymerization and hydrogenation rapidly occursin the cracked products, which are then passed to the condenser forreduction to liquid form whilst still under pressure.

The exit or operative pressure on the products from the previouscracking operation described in my said co-pending appli' cation whichare introduced through the pipe at will be about 135 lbs. per squareinch and the temperature will vary between 500 C. and 800 C. forexample, between 500 C. to 600 C. where gasolene is desired or from 600C. to 700 C. where aromatic hydrocarbons are desired.

The digester has already been described, the only remarks to be addedare that it is provided with a removable cap, 62, so that the fillingmaterial can; be removed at any time. Further an automatic sludge-valve63, is provided which keeps the liquid level at 63.63, as shown. .1

' The digester b consists of a, stout steel chamber 24 inches internaldiameter and 12 feet high, filled with short pieces of .1 inch ironpipe, such as illustrated in Figures 3 and 4. V f

Having thus described my invention, what I claim and desire to obtain byLetters Patent of the United States is:

. 1. The process which consists in subjecting the pre-cracked material,resulting from subjecting high boiling point hydrocarbons to a heatand'pressure cracking processin which the principal portion of the heatemployed isgenerated without subjecting thematerial to theinfiuence of asilent electric discharge, to the influence of a silent electricdischarge of sufficient intensity to materially polymerize. suchmaterials, wheieliy the same drogen is taken from the gas and caused topounds resulting from heat cracking of oils,

ated state and of a gas relatively rich in hybons whereby hydrogenistaken from the are substantially stabilized and otherwise improved.

2. In the process of cracking hydrocarbons and then of hydrogenatingpre-cracked unsaturated hydrocarbon compounds whilst in the dissociatedstate, the step which consists in subjecting a physical mixture of suchcompounds and of a gas rich in hydrogen to the discharge of a hightension electric current, thus causing rearrangement of the molecular.structure of the hydrocarbons whereby hydrogen is taken from the gas andcaused to unite with the unsaturated hydrocarbons to produce stablesaturated hydro-v carbons;

3..In the process of cracking hydrocar bons and then of hydrogcnatingpre-cracked unsaturated hydrocarbon compounds whilst in the dissociatedstate, the step which consists in subjecting a physical mixture of suchcompounds and of a gas'rich in hydrogen to the discharge of an electriccorona, thus causing rearrangement of the molecular structure of thehydrocarbons whereby hyunite with the unsaturated hydrocarbons toproduce stable saturated hydrocarbons.

4. The electrochemical process of treating pre-cracked unsaturatedhydrocarbon. comdrogcn to the discharge of a high-tension electriccurrent, thus causing rearrangement of the molecular structure of thehydrocargas and caused to unite with the unsaturated hydrocarbons to,produce stable saturated hydrocarbons. 1 6. The process of treatingpre-cracked h drocarbon compounds, resulting from til the cracking at acracking temperaturef'of high-boiling point hydrocarbons, which consistsinsujecting such products while in a nascent state and comprising amixturebf.

condensable and non-conde'nsable vapors and gases, the latter rich inhydrogen, to the action of an electric corona inorder to hydrogenate andpolymerize the condensable portions'thereof. w -7. The process whichconsists in subjectingthe PrG'QTaCkGdPIOduCtS from the cracking 1 ofhigh-boiling point hydfocrxaonslat a cracking temperature and Whilein-the presence of the uncondensztblegases,- rich in hydrogen, resultingfromsuch "'previous' treatment, to the action of an electric corona;

for a sufficient period o'f'time to effect sub-.

stantialhydrogenation and polymerization of such cracked products.-

8 The process of improving pre-cracked ""ussmu'rs corona .in order topolymerize and hydrogenate the same.

gned at New State of- New' York this 7th of February DONALD L. THOMAS.

York, in the county and

